Objective:
1) Assess variation in sunflower volatile composition among inbreds, hybrids and other germplasm for materials with established levels of resistance to sunflower insect pests; 2) conduct behavioral or physiological tests of insect response to volatile abundance or composition; and 3) if applicable, evaluate role of other semiochemicals in producing damage from sunflower insects.

Approach:
Sunflower germplasm in various stages of development will be grown in field or greenhouse conditions to provide samples of naturally-produced plant volatiles. Chemical analysis, including gas chromatography, will be used to identify and quantify components in volatile blends. Insect responses to volatiles will be evaluated indirectly with choice tests or directly with physiological tests (e.g., via electroantennogram). Additional field tests of resistance may be used to further validate patterns detected in germplasm not previously used for sunflower insect resistance.